There is an ever-increasing spotlight on environmental issues and as a response, we have noted our thoughts and our intended actions.
Most of the products we ship every day are a 3 layer self-adhesive construction:
- Face film
- Adhesive layer
- Release liner
1. Face films
These can be PVC, Polyester, Polyolefin (Polypropylene or Polyethylene).
- Plasticised PVC (Polyvinyl chloride) films are by far the most popular in the Sign and Digital industry, probably accounting for over 90% of demand.
It can be cut, pigmented, printed by nearly all technologies without expensive and energy consuming top coats, and most importantly is very durable outdoors, offering a service life several times longer than the alternatives.
PVC also consumes less energy during production than other plastics.
The raw materials for PVC are salt and oil, with salt making up the majority of the film, and there is no shortage of salt in the Ocean.
PVC is recyclable with number as its resin identification code.
Plasticisers, which incorporate Phthalates, are added to the PVC to make the film more flexible and practical to work with.
Other additives include heat stabilisers, UV stabilisers, lubricants and generally pigments.
As the Chlorine atom is a major part of the PVC monomer, PVC produces HCl upon combustion and can release Dioxins, which is a concern.
To investigate this further we visited modern electricity-generating plants using high temperature Energy from Waste incineration and they insist no Dioxins are created in the stack or the residual ash.
PVC is the third most popular plastic in the world, behind Polyethylene and Polypropylene.
- Polyester (PET) films only account for a small part of the market due to the high cost, the rigidity of the product and the need for a top coat for printing.
Polyester has the number .
Commonly used in packaging for plastic bottles and food trays.
- Polyolefin (Polypropylene or Polyethylene) films are beginning to make a small impact.
Polypropylene (PP) and Polyethylene (PE) have the same basic ingredients and the raw material is oil.
Polypropylene is recyclable .
PP is the second-most widely produced plastic and is used in packaging for dairy trays, microwave containers, etc.
The new UK bank notes are now manufactured from PP.
It is generally more rigid than PVC and cannot be printed without a top coat being applied, which adds to the cost and has a negative environmental impact as the coating requires energy to be dried in the ovens.
PP also has a shorter life outdoors.
Although Polyethylene is the most popular plastic in the world, PE films have made no impact in our industry.
Like PP, PE cannot be printed without a top-coat being applied which adds to the cost and environmental impact.
It also has a shorter life outdoors than PVC.
Used in packaging for bags, milk bottles, films and labels.
Polyethylene comes in a variety of densities, is recyclable and has the number or dependent whether high (HDPE) or low density (LDPE).
These are nearly all acrylic based in our industry.
In either solvent dispersions, water dispersions or UV cured format.
- Solvent based adhesives
These acrylic adhesives are dispersed in a chemical solvent to make them less viscous and then coated in a ‘thick’ layer.
They then pass through long heated ovens to evaporate off the solvent carrier.
These ovens can be over 50M in length and require a lot of energy to heat.
Solvent based adhesives offer excellent long-term performance but chemical solvents are expensive, and in Europe the solvents driven off in the drying cycle have to be re-captured, which adds to the cost.
- Water or emulsion based adhesives
These acrylic adhesives are dispersed in water to make them less viscous and then coated in a ‘thick’ layer.
These acrylic adhesives are less durable, have lower performance, are cheaper, and are generally more suitable for internal applications.
They still require a lot of energy to drive off the water in the ovens.
- UV cured adhesives
Our focus has turned in recent years to UV cured polyacrylates.
These have the same acrylic backbone as solvent adhesives, so have virtually the same performance as solvent based adhesives, but can be coated as ‘solids’, without the need for dilution, and are cured by UV, rather than traditional ovens.
They require less energy to manufacture and are less hazardous in the manufacturing process.
3. Release liners
These can be kraft, Polyethylene coated, or occasionally Polyester.
Release liners are one of the biggest waste factors in our industry, as they are almost part of the packaging in that they do not figure in the in-situ graphics.
Unfortunately, due to the silicone layer required to protect the adhesive, these cannot currently be recycled, leaving us with landfill or incineration as the only option.
All the papers we source are FSC certified which allows you to identify, purchase and use paper made from well managed forests and/or recycled sources.
Recycled papers are currently not used as base paper stock for our papers as they are of lesser quality and more expensive.
- The most popular liners are clay-coated krafts.
We are currently working on how we can reduce the weight of these papers but retain the performance our customers and some of the printer technologies demand.
The ‘lighter’ the paper, the less trees need to be used in the papermaking and the less mass there is to be disposed of.
It is a difficult balancing act between price, performance and environmental impact.
- The other main liners we use are Polyethylene coated, also known as PE or resin coated.
These liners are more stable under heating in printers and are less prone to cockling in changing humidity conditions, but are more expensive and have an extra layer of Polyethylene added to the back of the paper to improve performance.
How can we minimise our environmental impact?
The obvious way is to reduce the mass of the products we produce.
This has been underway for years now as a natural way to reduce costs and minimise price increases.
PVC films have come down in thickness from a 100µ average a few decades ago to a current average of around 75µ, without losing any performance.
Further reductions down to 50µ to 60µ are possible but opacity, handling, and the ability to accept high ink loads begins to be compromised.
When we get close to 50µ the film costs actually increase.
The adhesive thickness has also been reduced by around 10% in the same period; any further reductions may compromise the adhesive itself.
In addition, release liners have reduced from the traditional 140gsm thickness to the 125gsm to 135gsm range.
We currently believe 120gsm is probably the minimum market acceptable weight for graphics. Below 120gsm stability in printing and handling starts to become a major issue.
In terms of our packaging, we are also phasing out some of the polybags used to protect the boxed rolls and are attempting to swap the two plastic core plugs per box with either recycled plastic plugs or cardboard alternatives.
Although the films themselves are all theoretically recyclable, in practice it is not possible.
The film and adhesive combination is almost impossible to separate in the UK, and that is without the added complication of printing inks and laminates.
Landfill is both costly and unwanted, which leaves us with incineration to produce electricity in ‘Energy from Waste’ plants.
EU guidance emphasises that “generating energy from waste that cannot be recycled or reused can contribute to a circular economy and energy diversification, thereby reducing greenhouse gas emissions from the waste sector”.
These plants have been around in the UK for many years now and originally were just incineration plants.
In the last few years some have been adapted to use the heat from burning waste to create superheated steam and drive turbines to generate low-carbon electricity.
The incineration processes have been improved with higher combustion temperatures, and increased burn time to ensure complete oxidation.
All the chlorine , the source of Dioxins, is converted to HCl or inorganic chlorides, the HCl is neutralised in the scrubber while CO² is vented to the atmosphere and the inorganic chlorides are incorporated into the ash.
We have visited an Energy from Waste plant, operated as a joint venture by Grundon Waste Management and Viridor.
The Lakeside EfW facility at Colnbrook near Slough has been operational since 2010.
This plant processes over 450,000 tonnes of waste per year, generating 37MW of power, which is enough to provide electricity to 56,000 homes.
They send nothing to landfill. Emission Limit Values are strictly regulated through the Integrated Pollution Prevention and Control regime and are currently monitored by the Environment Agency.
All emissions from the stack comply with the most stringent UK and European pollution control standards.
The Air Pollution Control residues from the filters, the fly ash and the Incinerator Bottom Ash are all recovered.
These reactive residues are then treated by using Accelerated Carbon Technology to make a recycled aggregate, which is then used as a substitute for naturally extracted aggregate in road building.
There are currently 48 EfW plants in the UK, still way below the number in countries such as France, Germany, Sweden etc.
As we see it, the advantages of EfW are:
- 100% diversion from landfill
- Reduce disposal costs, by sending waste to Energy from Waste facilities means no Landfill Tax
- Generate renewable electricity as your non-recyclable waste generates power for the National Grid, currently we believe around 2% of all UK electricity is produced by EfW
- These schemes have been taking our waste for years and seem happy with the mix our industry feeds them with
REACH is a regulation of the EU, to protect health and the environment from the risks posed by chemicals.
It had an impact on PVC films a few years back as certain chemicals used in pigments were banned in the EU, including pigments based on lead chromate.
These changes made some products less opaque and some products had to change shade. Some phthalates used for plasticisers were also banned such as DEHP.
All our EU suppliers were fully on board with these changes and continue to monitor and adhere to all the new regulations.